Aspects of the invention relate to a TV program displaying method and a vehicle-mounted displaying device employing such a method.
A vehicle-mounted device such as a car navigation system generally includes a displaying device and has a function of displaying a TV program on the displaying device. Such a vehicle-mounted device is typically configured such that a TV function is executed as a background process, while, for example, the navigation function can be executed as a foreground process when the vehicle (e.g., a car) is being driven to run. That is, a TV screen is not displayed when the vehicle driven and only the sound of the TV program currently selected is output. An example of such a vehicle-mounted device is disclosed in Japanese Patent Provisional Publication No. P2002-101355A (hereinafter, simply referred to as '355 publication).
In a case of the car navigation system, when the navigating function is executed as the foreground process and the TV function is executed as the background process, a map for navigation is displayed on the displaying device, while the sound of the TV program is output from a speaker. In such a situation, if a user of the car navigation system switches a TV channel to another program, the sound is switched to the changed program. According to the '355 publication, in such a case, information regarding the switched channel (e.g., a TV station name, channel number, etc.) is superimposed, in the form of text, on the navigation map.
Sometimes, such text information is insufficient to recognize the content of the switched program. It may be possible to display further information regarding the switched TV channel. However, too much information may hinder the image for the navigation, which obstacles a driver from driving using the navigation function. Further, too much text information requires the driver's attention, which should be avoided in view of safety driving.